Good stuff as usual man. I've worked with rye, wbs, and popcorn and prefer popcorn as well. It's very easy to get the water content wrong with wbs. I don't know where some guys over at the mushroom forums get off calling popcorn "inferior spawn" or whatever. Rye is definitely better but I wouldn't exactly say popcorn is "inferior." Then again, a lot of those guys condemn coir, so I am beginning to doubt the wisdoms of some of the guys over there. However I digress.
You've mentioned fruiting grains straight several times now and I'm curious how you do that. You just take the lid off the jar and place in a fruiting chamber of some kind or does it require a casing?